> BTW eks, you asked about reusing TSDC.
yeah, it is normally not a big deal to allocate everything again, but these
arrays are not necessarily small, I guess it would make sense to open this
possibility.
do you think where would be better to add reset(), TSDC or to Collector?
I would even suggest to change clear method to become clear(Object sentinel) to
PQ instead... or to add such a method (backwards compatibility) ...
Another question:
Looking at the code in PQ, it was not really clear to me why sentinels have to
be allocated maxSize times in initialize method? I am talking about:
// If sentinel objects are supported, populate the queue with them
Object sentinel = getSentinelObject();
if (sentinel != null) {
heap[1] = sentinel;
for (int i = 2; i < heap.length; i++) {
heap[i] = getSentinelObject(); //Why not simply heap[i] = sentinel;
}
size = maxSize;
}
getSentinelObject() creates new object every time (HitQueue)
are these objects mutable?
----- Original Message ----
> From: Shai Erera <ser...@gmail.com>
> To: java-user@lucene.apache.org
> Sent: Wednesday, 30 September, 2009 18:11:03
> Subject: Re: TSDC, TopFieldCollector & co
>
> BTW eks, you asked about reusing TSDC. PQ has a clear() method, so it can be
> reused. Only currently it's final and nullifies the array. We'll need to
> un-final it, and then override in HitQueue to just reset the ScoreDoc
> instances to be sentinels again. And of course add a reset() method to TSDC.
>
> On Wed, Sep 30, 2009 at 5:26 PM, eks dev wrote:
>
> > Thanks Mark, Shai,
> > I was getting confused by so many possibilities to do the "almost the same
> > thing" ;)
> >
> > But have figured it out by peeking into BoolenQuery code that decides if
> > "out of order" should be used..., BQ will pick the right TSDC ... I like it,
> > option 1 it is minimum user code.
> >
> > Cheers, eks
> >
> >
> >
> > ----- Original Message ----
> > > From: Shai Erera
> > > To: java-user@lucene.apache.org
> > > Sent: Wednesday, 30 September, 2009 17:12:38
> > > Subject: Re: TSDC, TopFieldCollector & co
> > >
> > > I agree. If you need sort-by-score, it's better to use the "fast" search
> > > methods. IndexSearcher will create the appropriate TSDC instance for you,
> > > based on the Query that was passed.
> > >
> > > If you need to create multiple Collectors and pass a kind of
> > Multi-Collector
> > > to IndexSearcher, then you should create TSDC according to Mark's example
> > > above.
> > >
> > > Shai
> > >
> > > On Wed, Sep 30, 2009 at 4:57 PM, Mark Miller wrote:
> > >
> > > > If you want relevance sorting (Sort.Score not Sort.Relevance right?),
> > > > I'd think you want to use TopScoreDocCollector, not TopFieldCollector.
> > > > The only reason to use relevance with TopFieldCollector is if you you
> > > > are doing a nth sort with a field sort as well.
> > > >
> > > > You don't really need to worry about things like turning off the max
> > > > score tracking here - its just going to be the first doc on the queue.
> > > >
> > > > You also do want to specify whether or not to collect docs in order if
> > > > you care about performance:
> > > >
> > > > public static TopScoreDocCollector create(int numHits, boolean
> > > > docsScoredInOrder)
> > > >
> > > > ie:
> > > >
> > > > TopScoreDocCollector.create(nDocs, !weight.scoresDocsOutOfOrder());
> > > >
> > > > Which means you just want option 1.
> > > >
> > > > --
> > > > - Mark
> > > >
> > > > http://www.lucidimagination.com
> > > >
> > > >
> > > >
> > > > eks dev wrote:
> > > > > Hi All,
> > > > >
> > > > > What is the best way to achieve the following and what are the
> > > > differences, if I say "I do not normalize scores, so I do not need max
> > score
> > > > tracking, I do not care if hits are returned in doc id order, or any
> > other
> > > > order. I need only to get maxDocs *best scoring* documents":
> > > > >
> > > > > OPTION 1:
> > > > > TopDocs top = ixSearcher.search(q, filter, maxDocs);
> > > > >
> > > > > OPTION 2:
> > > > > final TopScoreDocCollector tfc =
> > TopScoreDocCollector.create(maxDocs,
> > > > false);
> > > > > ixSearcher.search(q, filter, tfc);
> > > > > TopDocs top = tfc.topDocs();
> > > > >
> > > > >
> > > > > OPTION 3:
> > > > > final TopFieldCollector tfc =
> > > > TopFieldCollector.create(Sort.RELEVANCE, maxDocs,
> > > > > false /* fillFields */,
> > > > > true /* trackDocScores */,
> > > > > false /* trackMaxScore */,
> > > > > false /* docsInOrder */);
> > > > >
> > > > > ixSearcher.search(q.weight(ixSearcher),filter, tfc);
> > > > > TopDocs top = tfc.topDocs();
> > > > >
> > > > >
> > > > > what are the pros and cons?
> > > > > If I read javadoc correctly,
> > > > > - OPTION 1 tracks max score and delivers doc Ids in order (suboptimal
> > > > performance for my case)
> > > > > - OPTION 2 I do not know abut max score tracking, but doc Ids are not
> > > > required to be in order
> > > > > - OPTION 3 looks like exactly what I want, but one performance
> > comment in
> > > > javadoc about Sort.RELEVANCE made me think if that is the fastest way?
> > > > >
> > > > > What would be recommended here, any other options to achieve the
> > fastest
> > > > search with above defined conditions (no max score tracking and doc id
> > order
> > > > irrelevant)? OPTIN2 looks nice, but as said, I am not sure about max
> > score
> > > > tracking?
> > > > >
> > > > > Thanks,
> > > > > eks
> > > > >
> > > > >
> > > > >
> > > > >
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> > > >
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